This invention relates to a method of, and an apparatus for, assembling a vehicular driving shaft in which a universal joint unit such as a bell type or tripod constant velocity joint or the like is attached to each of both ends of the driving shaft.
It has been usual heretofore with a conventional driving shaft assembly line of this kind, as disclosed in the Japanese Unexamined Patent Application Publication Tokkashio 61-284333, that a driving shaft held in its lateral laydown posture is sent intermittently to each of plurality of assembling stations. Component parts of a joint unit are assembled to the shaft at each of the assembling stations by means of an assembling device provided on one side of each of the assembling stations.
In the assembly line of this kind, some of the component parts of the first joint unit which are to be attached to one end of the driving shaft are attached to that one end at one of the assembling stations and thereafter some of the component parts of the second joint unit which are to be attached to the other end of the shaft are attached to that other end at the next assembling station. Then, the remainder of the component parts of the first joint unit and those of the second joint unit are attached alternately to the one end and to the other end, respectively.
In the foregoing assembly line, the driving shaft which is a long-sized article is conveyed along the assembly line while in a lateral laydown posture, so that a conveying line or passage therefor has to be made wider and thus requires much space. In addition, when a component part which is relatively heavy is attached to one end of the driving shaft, the shaft becomes asymmetrical in weight (balance) and this makes it difficult to convey the shaft in its balanced posture. Therefore, a first object of the present invention is to solve these problems including the space requirement and the unbalanced posture of the shaft during conveying thereof so that the conveying line space may be reduced and the driving shaft can be conveyed in a balanced posture.
In each assembling station of the prior assembly line, a backup unit for centering a driving shaft and holding it in the centered position is provided to face the end of the shaft other than that to which component parts of the joint unit are being attached. However, in the above-described assembly line in which some of the component parts of the first and the second joint units are attached alternately to each of both ends of the driving shaft in one round of the assembling and some others in next round of the assembling, if one of the first and the second joint units, say, the second one, is changed to a different type, it becomes necessary to change not only the specification of each assembling device for the second joint unit provided at each assembling station but also the specification of a backup unit provided at each assembling station for the first joint unit in order to have it adapted for the corresponding component parts of the second joint unit assembled at the preceding assembling station, so that it takes more time and work to carry out the change. A solution to this problem is the second object to be attained by the present invention.